Method of cooling compressed blocks of dehydrated vegetable matter



y 1950 G. 5. SMITH METHOD OF COOLING CQMPRESSED BLOCKS OF DEHYDRATED VEGETABLE MATTER Filed Jan. 25, 1948 igil.

INVENTOR. GEORGE S. SMTH ATTORNEYS Patented May 16, 1950 METHOD OF COOLING COMPRESSED BLOCKS F DEHYDRATED VEGE- TABLE MATTER George S. Smith, Berkeley, Calif., assignor to the United States of Americaasrepresented by the Secretary of Agriculture Application January 23, 1948, Serial No. 4,051

(Granted under the act or March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 4 Claims.

This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed if patented in any country, may be manufactured and used by or for the Government of the United States of America throughout the World for governmental purposes without the payment to me of any royalty thereon.

This invention relates to the compression of materials and particularly to the compression of dehydrated vegetable foods.

It is well known in the art that dehydrated vegetable foods, such as dehydrated carrots, potatoes, beets, onions, rutabagas, and sweet potatoes, can be compressed to decrease their bulk and thus effect economies in packaging, shipping, and storage. It is generally necessary that these dehydrated foods be heated prior to compression since heating avoids fracturing of the material, increases cohesion, and decreases the degree of pressure required. However, the blocks of dehydrated material produced in this conventional manner will expand as soon as they are removed from the press and will continue to expand as long as they are warm. Thus, if a block of material is removed from the press and set aside, it will expand in a non-uniform'manner and thus the material is diificult to package and'the-bulk "thereof is objectionably'increased.' Under certain conditions of press operationjthe blocks expand to such an extent after removal from the press that they break apart and consequently must be discarded. It is known that, if the block of dehydrated food is removed from the press and restrained from expanding until it cools to near room temperature, the block will retain its size and shape.

An object of my invention is to 'accornpli-shthis restraining or limiting of expansion ofthe compressed block's during th'e'time required to cool them to near room temperature. a A further object of this inventionis to provide an apparatus for holding compressed blocks of material during cooling, particularly dehydrated vegetable foods, and for permitting cooling under restraint, to allow only partial expansion.

Another object of this invention is to provide an apparatus for holding blocks of material during cooling, and limiting expansion'thereof, said apparatus being simple in design and capable of being rapidly loaded and rapidly unloaded.

In this device the expansion of the blocks is limited by restraint applied to those faces of the block which were normal to the direction of pressure application used in making the'block.

2 In the ordinary press used in forming the block the'pressure is applied to the top and bottom faces of the block. The block so formed is then placed in my novel block holding apparatus so that restraint-is applied to the top and bottom faces. No

provision need be made to restrain expansion of the four other faces. In this manner a certain amount of expansion does occur but it is substantiallynegligible, or insufiicient to cause breaking or change in shape, and the cooled block has a permanent volume. In its preferred form the method is essentially one in which blocks of heated, compressed material are cooled under restraint to allow only partial expansion, by establishing a pile of said blocks between a top shelf and a bottom shelf, said blocks being inserted in said pile series as they are produced, starting from the top, each block being separated from its adjacent block by a barrier freely movable laterally and upwardly, the top shelf, bottom shelf and barriers defining a series of 'equalsized, blockholding compartments, and allowing the blocks to cool and expand within the limits of the block- 'holding' compartments.

through holes in the lugs and'which screw into the uprights. Shelves 9', I0, H 12, that is, all of the shelves below shelves 6, rest on cleats 4 and preferably are unfastened and therefore free to move upwardly within the limits of the cleats, and can be removed laterally.

The distancefrom the bottom of each shelf tothe top of the next lower shelf represent the "final height of the cooled block. This distance is somewhat greater than the height of the block directly after it is formed.

The block holding apparatus is loaded as follows:

The blocks from the press wherein they are prepared are loaded into the apparatus from the top down. Shelf 6 is first fixed in place by application of lugs 'l and screws 8 as previously described. The'first block 14 is placed on shelf 55the second block 15 is placed on shelf ill, the

third block'is placed on shelf I l, the fourth block is placed on shelf l2, and the fifth block is placed on base 5. As previously mentioned the blocks coming from the press are somewhat smaller than the distance from the bottom of one shelf to the top of the next lower shelf, so that the blocks are easily slid onto each shelf. Expansion of the blocks begins immediately, but this causes no harm and does not prevent loading of the shelves. For example, as first block it expands it fills the entire distance from the bottom of shelf 6 to the top of shelf 9 (as shown in Fig. 1) but can expand no further because shelf 6 is fixed by lugs 1 and shelf 9 rests on cleats G. The second block i5 placed on shelf also expands but lags behind block l4 because it was taken from the press after the first block. Consequently, its limit of expansion is the distance between the bottom of self 9 and the top of shelf l0. Shelf 10 cannot be forced down because it rests on cleats. Shelf 9 cannot be forced up because the first block is in place and wedged tightly between shelves 6 and 9. In the drawing, block I is shown as it appears when placed in the apparatus.

This holds for the other shelves and blocks. In 5 7 each case the fact that topmost shelf 5 is fixed and that the blocks above the one in question are already completely expanded, or at least expanded further than the one in question, prevents the upward movement of any of the shelves. After the section bounded by vertical members I and 2 is filled the second section is filled in the same manner. The apparatus is then wheeled to a suitable place where cooling is allowed to proceed to completion.

Uniform blocks are obtained because the expansion of the blocks is a function of time. The blocks are all of the same composition and are produced in series. The first block produced will be considerably expanded by the time the second is placed in the device. This expansion is rapid, being a matter of seconds.

The blocks of heated dehydrated material are produced by a suitable press in series. In operation, the holding apparatus is located close to the press. The operator takes each block as it is ejected from the press and slips it into the holding apparatus.

The unloading of the block holding device is as follows:

After the blocks have cooled to the proper tem-- perature, lugs I are removed. Shelf 6 is then removed. The topmost block is is lifted or slid opt. Removal of the topmost block allows shelf 9 to be lifted up and then the block second from the top can be slid out. Removal of the second block allows shelf [0 to be lifted and thus the third block can be slid out, and so forth.

If it is desired, the shelves may be of such length that two or more blocks of material may be placed side by side on each shelf.

No matter how many sections or shelves are provided in the apparatus, if a small batch of material is to be handled all the shelves need not be utilized. As previously explained, the expansion of the first block placed in the aparatus locks the second shelf from the top and any number of desired blocks can be placed beneath the first block. If the press has to be shut down for any length of time, and then started up again, the blocks produced can be slid in place in the usual manner.

In order to obtain finished blocks of uniform size it is usually desirable to load the apparatus from the top down as described above. However,

if the blocks are produced rapidly so that the first will not expand materially before the next one is produced, then the shelves can be loaded in any desired sequence. In such case, however, the blocks may not be of uniform size upon cooling. For this reason loading from the top down is generally preferred.

The apparatus is subject to obvious variation, and the method may be carried out in other types of apparatus.

Instead of casters, the apparatus may be supported on a turntable, or mounted for rotation about a central vertical axis.

Although the apparatus of this invention is particularly adapted to the holding of compressed blocks of dehydrated vegetable foodstuffs, its use need not be so limited. The apparatus can be applied to holding blocks of compressed tobacco, hops, dehydrated apples, and other materials.

Having thus described my invention, I claim:

1. A method of preparing compressed dehydrated vegetable food in which the food is heated and compressed into blocks by applying pressure to two opposite faces of the blocks, the improve ment comprising permitting the blocks to cool and expand and limiting the amount of expansion of the blocks by applying restraint to the said faces, said restraint being applied in sequence to a number of successively cooling and expanding blocks successively removed from the compression treatment; a first compressed block being placed between two surfaces, delimiting the movement of one of said surfaces away from the second surface, delimiting the movement of the second surface in the direction away from the first surface but not in the direction toward the first, permitting the placed first block to cool and expand at least partly, placing a second compressed block between third and fourth surfaces, the third surface being restrained from movement away from the fourth surface by the expansion of the first block, delimiting the movement of the fourth surface away from the third surface.

2. The process described in claim 1 in which the surfaces are disposed horizontally, one above the other, the first surface being uppermost and being fastened in position, the other surfaces being unfastened, the blocks being inserted in sequence, from the top downwardly; whereby all of the blocks become, after expansion, held in position by the uppermost fastened surface and all are removable by unfastening the said uppermost surface; and unfastening the topmost surface and removing the blocks.

3. A method of cooling compressed hot blocks of dehydrated vegetable material, comprising inserting a first block of said material, as it is removed from compression, below a top fixed barrier surface and resting it upon a lower upwardly movable barrier surface, allowing the first block to cool and expand at least partly, inserting a second block of said material, as it is removed from the compression, subsequently to the removal of the first block from the compression, between the lower upwardly movable barrier surface and a second still lower barrier surface, and allowing all of the blocks to cool and to expand within the limits of the barrier surfaces the expansion of the first block locking the upwardly movable barrier surface.

4. A method of obtaining uniform sized blocks of compressed, dehydrated vegetable foodstuffs, comprising compressing warm dehy- 5 drated vegetable material into blocks by applying pressure to two opposite faces thereof, removing the blocks in sequence from the compression, permitting each block to cool to room temperature, limiting the expansion of the cooling blocks in the direction normal to said two faces by stacking the blocks vertically, one below the other, in sequence from the top to the bottom, upon upwardly movable barrier supporting surfaces, the upper surface of the uppermost block being delimited in its expansion upwardly by a fixed top barrier surface, thus utilizing the expansion of the upper blocks to define the limits of expansion of the lower blocks.

GEORGE S. SMITH.

REFERENCES CITED The following references are of record in the file of this patent: 

1. A METHOD OF PREPARING COMPRESSED DEHYDRATED VEGETABLE FOOD IN WHICH THE FOOD IS HEATED AND COMPRESSED INTO BLOCKS BY APPLYING PRESSURE TO TWO OPPOSITE FACES OF THE BLOCKS, THE IMPROVEMENT COMPRISING PERMITTING THE BLOCKS TO COOL AND EXPAND AND LIMITING THE AMOUNT OF EXPANSION OF THE BLOCKS BY APPLYING RESTRAINT TO THE SAID FACES, SAID RESTRAINT BEING APPLIED IN SEQUENCE TO A NUMBER OF SUCCESSIVELY COOLING AND EXPANDING BLOCKS SUCCESSIVELY FROM THE COMPRESSION TREATMENT; A FIRST COMPRESSED BLOCK BEING PLACED BETWEEN TWO SURFACES, DELIMITING THE MOVEMENT OF ONE OF SAID SURFACES AWAY FROM THE SECOND SURFACE, DELIMITING THE MOVEMENT OF THE SECOND SURFACE IN THE DIRECTION AWAY FROM THE FIRST SURFACE BUT NOT IN THE DIRECTION TOWARD THE FIRST, PERMITTING THE PLACED FIRST BLOCK TO COOL AND EXPAND AT LEAST PARTLY, PLACING A SECOND COMPRESSED BLOCK BETWEEN THIRD AND FOURTH SURFACES, THE THIRD SURFACE BEING RESTRAINED FROM MOVEMENT AWAY FROM THE FOURTH SURFACE BY THE EXPANSION OF THE FIRST BLOCK, DELIMITING THE MOVEMENT OF THE FOURTH SURFACE AWAY FROM THE THIRD SURFACE. 